Ethyne

Ethyne (also known as acetylene) with formula C₂H₂ is a potential resource molecule for future gemstone metamaterial on chip factories. It received especially much attention in theoretical analysis due to a few advantageous properties.

• low hydrogen content
• reactive highly unsaturated carbon-carbon triple bond
• high energy compound

Another interesting (energy devoid) resource molecule for carbon would be carbon dioxide CO₂.
But it wasn't investigated in detail in the context of piezochemical mechanosynthesis as of yet (2021).

Alternate carbon resource molecules

Carbon dioxide tapped directly from the air. Given renewable or nuclear energy this would be "carbon negative".

Methane:
There will be quite a bit of ultra pure water as a side product though due to methanes high hydrogen content.
Maybe methane is not a good carbon resource for for deep space operations where you either need to bring the oxygen or store pure hydrogen.
More processing steps may influence the internal efficiency negatively. But efficiency gains o external conventional chemical preprocessing must be considered too.

Possibly Carbohydrates like e.g. sugars?
Handling floppy chain molecules are resource molecules may pose additional design challenges.
Also sugars like to from rings and self polymerize.

Notes on interesting properties of Ethyne

Today Ethyne (also known as acetylene) is mainly used for gas welding (oxyacetylene welding).

• It can create an especially hot flame
• It can create a reducing environment good for welding

Storing etyne in large quantities in pure form can be dangerous since (given enough pressure and temperature) it likes to self polymerize in a runaway exothermic reaction. Etyne gas tanks are thus filled with a compound that counteracts this self polymerization tendency. Lowering pressure by adsorption and slowing reaction kinetics (to check).

Related

• Resource molecule – Moiety
• Acetylene sorting pumps are supposed to sort/purifies these molecules.
• Piezochemical mechanosynthesis
• Carbon dioxide
• Polyyne rods

External links

• Calcium_carbide CaC₂ (leave to Wikipedia - please come back again) – released acetylene on contact with water
• Carbide_lamp (leave to Wikipedia - please come back again)